How to Compress PDF Files in Java

Install IronPDF in Java Maven Project

• To install IronPDF in a Maven project, you will need to add the IronPDF Maven repository and dependency to your project's pom.xml file.

• Next, add the IronPDF dependency by adding the following to the section of your pom.xml file:

  <dependency>
      <groupId>com.ironsoftware</groupId>
      <artifactId>ironpdf</artifactId>
      <version>your_version_here</version>
  </dependency>

  <dependency>
      <groupId>com.ironsoftware</groupId>
      <artifactId>ironpdf</artifactId>
      <version>your_version_here</version>
  </dependency>

  XML
• Save your pom.xml file and run MVN install to install the IronPDF dependency.

Once you have completed these steps, you should be able to import and use the IronPDF classes in your project.

Compress PDF File

This code is a Java program that uses the IronPDF library to compress a PDF document.

import com.ironsoftware.ironpdf.*;
import java.io.IOException;
import java.nio.file.Paths;

public class App {
    // Main method to compress PDF
    public static void main(String[] args) throws IOException {
        // Define the path of the source PDF file
        String src = "C:\\Image based PDF.pdf";

        // Load the PDF document from the specified file path
        PdfDocument pdf = PdfDocument.fromFile(Paths.get(src));

        // Compress images within the PDF to 60% of their original quality
        pdf.compressImages(60);

        // Save the compressed PDF to a new destination
        pdf.saveAs(Paths.get("assets/document_compressed.pdf"));

        // Compress images to 90% with additional resolution scaling
        // This can potentially reduce file size further by scaling image resolution
        pdf.compressImages(90, true);

        // Define the path where the final compressed PDF will be saved
        String dest = "C:\\Compressed.pdf";

        // Save the final compressed PDF
        pdf.saveAs(Paths.get(dest));
    }
}

import com.ironsoftware.ironpdf.*;
import java.io.IOException;
import java.nio.file.Paths;

public class App {
    // Main method to compress PDF
    public static void main(String[] args) throws IOException {
        // Define the path of the source PDF file
        String src = "C:\\Image based PDF.pdf";

        // Load the PDF document from the specified file path
        PdfDocument pdf = PdfDocument.fromFile(Paths.get(src));

        // Compress images within the PDF to 60% of their original quality
        pdf.compressImages(60);

        // Save the compressed PDF to a new destination
        pdf.saveAs(Paths.get("assets/document_compressed.pdf"));

        // Compress images to 90% with additional resolution scaling
        // This can potentially reduce file size further by scaling image resolution
        pdf.compressImages(90, true);

        // Define the path where the final compressed PDF will be saved
        String dest = "C:\\Compressed.pdf";

        // Save the final compressed PDF
        pdf.saveAs(Paths.get(dest));
    }
}

The code imports the IronPDF library and the necessary Java classes for file handling. The main method of the App class reads a PDF document called "Image based PDF.pdf" from the "C:" directory, compresses the images in the PDF by 60%, and saves the new compressed version as "document_compressed.pdf" in the "assets" directory.

Then, it compresses the images in the PDF by 90% and saves the resulting PDF file as "Compressed.pdf" in the "C:" directory. The second optional parameter can scale down the image resolution according to its visible size in the PDF document, which might lead to image distortion with some configurations.

You can see the comparison between the compressed file and the original PDF file.

Before Compression

After Compression